As the scale of electronic components decrease, the pressure increases to find alternative materials and methods for the formation or deposition of multi-component films, layers and coatings on substrates or wafers having desirable electrical and physical properties. In particular, semiconductor devices of future generations require thinner dielectric films having a high dielectric constant for capacitors having increased capacitance.
Among the most promising candidates for dielectric materials are metal oxides, such as a tantalum oxide (Ta2O5), which are known for use in generating insulating films that exhibit improved insulating properties. Such films have been formed by chemical vapor deposition (“CVD”) or metal organic chemical vapor deposition (“MOCVD”) using two or more different metal precursors.
The use of metal amide-based precursors for the CVD of oxide and nitride has been reported. For example, tantalum oxide (Ta2O5) and tantalum nitride (TaN) have been deposited from a tantalum amide/imide type precursor R—N═Ta(NR2)3, wherein R is an alkyl group. Finally, it has been reported in the literature that tantalum oxynitride (TaOxNy) is a better dielectric than commonly used tantalum oxide (Ta2O5) for capacitor applications.
However, prior art deposition chemical vapor deposition techniques using two or more different metal precursors are increasingly unable to meet the requirements of advanced thin films. The use of two or more different metal precursors to form the layers in the MIM capacitor can result in incompatibility and instability between the layers detrimentally effecting the electrical properties of the ultimate capacitor. In addition, the use of two or more different metal precursors increases production time and necessitates a more complex CVD reactor configuration, and therefore increases expense.
Accordingly, there is a need for a method for forming MIM capacitors increases compatibility and stability between the layers, reduces production time and simplifies the reactor configuration, thereby reducing fabrication costs. It is desirable that the MIM capacitors produced by the method exhibit improved electrical properties, and uniformity between MIM capacitors formed across a single substrate or multiple substrates and in sequentially performed processes. It is further desirable that the MIM capacitors produced by the method exhibit no undesired reaction between adjacent layers or phase separation between the layers of the capacitor structure.